Differential coal flotation



Aug. 10, 1 926. 1,595,131

J. V. QUIGLEY DIFFERENTIAL COAL FLSOTATION Filed May 24, 1922 INVENTOR My m 25 BYW- 5! i 7 4 A TT RNE Y5 enemies 1c, 1926. f

A T E N Jfil ilfi m QUIGLEY, GE ALAMIEDA, CALIFORNIA, A SSIGNOR T0 MINEMLS SEPARA- TIQN NQB'E'H AMERICAN CQBZPORATION, OF NEW YORK, N. 2., A. COBIQBATION 9F HAEYEJMID.

DIFFERENTIAL COAL FLOIA'IIOH.

This invention relates to the froth-flotation concentration of coal-bearin materials and as herein described is applied to the selective flotation of bituminous coal so as to produce from a single lot of coal one or more concentrates which are relatively richer in carbon and have a lower content of sulphur than the untreated cosh in the form of the invention herein disclosed the bituminous coal is first agitated "in the absence of any added agent to produce a coalbearing froth, which is then separated. There is then added to the pulp containing the remainder of the coal, an agent such as petroleum oil, and the nip is further agitated to produce a secon coal-bearingfroth The two froths are separately collected and are found to vary quite widely from each other in character.

it is found that certain bright-coal ingredients are preferentially separated in the first froth; produced in the absence of added agent. These ingredients may have an ash approximately of the composition of .the' original plant ash, and this first froth, carrying these ingredients. contains much less ash than the original coal. The concentrete thus obtained also contains much less sulphur than the original coal.

it is found that the second froth, produced with the addition of an agent, contains a relatively large proportion of other coal ingredients dull in appearance to the naked eye.

The cool of the first froth is usually of great purity and well adapted for use in arts demanding a coal of this character, and is particularly "free from substances detrimental to the production of metallurgical coke. T he coal. oi the second froth is about of the richness of the original coal, or slightly richer. The tailings are largely composed crash and contain a considerable part of the sulphur.

The examples herein described were car ried out in a subaeration machine of the kind shown in sectional side view in the acconn panying drawing.

This machine has an agitation chamber 1, I

of rectangular cross-section, provided with an agitator 2 turning near the bottom or" the chamber and carried by a shaft 3, which is journaled in overhead bearings i and 5, and has a driving pulley 6, at the top, and is supported just below the pulley by a suitable thrust bearing 7.

To form a froth, the agitator 2 is driven in the proper direction at a suitable speed and air is thereby drawn in through a bottom pipe 9, suitably connected by a iii-extension to an upright pipe 10, extending above the level of the pulley in the chamber 1 and provided with a valve 11 to control the admission of air beneath the agitator 2. A suitable bafiie 12 is located above the agitator :2, and is shown as formed of intersecting metal sheets 13 and 14, set at right angles to each other.

Alongside of the agitation chamber 1 is formed a spitzlrasten 18 and the wall 1'? between the agitatiouchamber and the spitzhasten terminates at the top below the pulp level, and provides communication at'the bottom between the agitation chamber and spitzkasten, thus permitting the pulp to flow over the top of this partition into the spitzhasten and to'fiow downward and back from the spitzkasten into the agitation chamber.

A draining opening 24, closed by a plug 25, is located in the bottom of the agitation chamber. p

The following are examples of procedures embodying my invention:

1. A coal from the United States Coal and Coke Company taken from mine No. 40 at Phillipi, West Virginia, was crush-ed d1" to pass through a lO-mesh Tyler screen, t was then thoroughly mixed with water to form a pulp and was agitated for minutes to form a first coal-bearing froth concentrate A, which was then removed. This first concentrate contained a large proportion of bright coal. There was then added one pound per ton ofa-light stove oil made by the California Fetroleum Company from California crude having an asphalt base. The oil had a gravity of to Baum, a

flash point of 160, a fire point or" 190, coo

talned a high percentage of kerosene oil and no more than 4% oi asphalt. When agitated with this oil for 15 minutes the remainder of the pulp yielded a second coalbearing froth concentrate B. This second concentrate contained a large proportion of till dull coal. The results are shown in the following table:

% covery 2. A coal from mine No. 3 of the same company at the same place was similar] crushed and then reground wet in a ball mi 1 for 5 minutes, resulting in approximately tated in the same machinefor 12 minutes yielding a first coal-bearing froth concentrate A, largely bright coal, which was col- -lected for a period of 12 minutes. There was then added to the remainder of the pulp 1.25 pounds per tonof the same light stove oil and a itation was continued for 13minutes pro ucing a second coal-bearing froth concentrate B, largely dull coal. The results are shown in the following table:

Wt. Wt. Ash. 7, s. fi' gig 691 Y 100. o a as 0.15

320 46.0 3.0 0.55 99 9 sea 48.0 1.4 0.66

7 Re- Ash. f

Wt. s.

4. A coal from the Westmoreland Coal and Coke Company, Legonia, Pennsylvania, was crushed dry to ass a 10-mesh standard Tyler screen and t en reground in a ball mill for 5 minutes to produce approximately 100-mesh material. The coal was then made into a pulp and agitated in the subaeration machine without any reagent for 13 minutes. During this time a first coal-bearing froth concentrate A, largely bright coal, was 001- 66 lected. The same light stove oil was then 100 mesh grinding. It was similarly agl- A, largely bright coal, was collected. There added at the rate of one pound per ton and the pulp was reagitated' for a period of '12 minutes, producin a second coal-bearin froth concentrate ,largely dull coal, WlllCfi was collected. The results are shown in the following table:

. 7 0- Wt. Wt. Ash. s cgvem lIeads. I 599 100.0 15.13 1. 2a Conc.A-. 286 41.1 1.s 0.9a Cone. B... 212 45.4 10.0 1.32 Tallings 51 a. a so. 0 a. 19

It will be observed that in every case a larger proportion of the ash went into the.

tailings and that a substantially larger prothan was retained in the concentrates.

It will be noted that this method of coal portion of the sulphur Went into the tailings concentration produces a means for-economically recovering the coaland at the same time dividing it into portions each having valuable properties and each especially suited for special purposes in the arts.

That is, according to the present invention, one concentrate is separated consisting of superior coal which has been floated in a froth without the addition of added mineral-frothing agent or oil, and thereafter another concentrate is separated consisting of inferior coal which was floated as a froth in the presence of suitable added agent or oil, while the final tailings are usually discarded. No claim is-broadly made herein to the concentration of coal by froth-flotation wherein the process is begun in the absence of any added mineralfrothing agent or oil and is completed by the aid of such an a cut or oil or both. The latter invention is escribed and claimed in the application of William Truran, Serial No. 563,341, filed concurrently herewith.

It is obvious that in the embodiment of this invention in the concentration of coalbearing'materials to which it is applicable the agents used and the PIOPbItIODS in which they are added and the details of operation will be adjusted to the particular requirements in each instance as determined by test and trial as. is well known in this art.

I claim 1. The process of concentrating coal-bearing material which consists in agitatin and aerating a pulp of the suitably groun material to roduce a coal-bearing froth without additlon of an a ent and se arating and segregatin'gthe frot then adding an agent tothe. depleted pul and subjecting the depleted pulp to farther agitation and aeration to form a second coal-bearing froth, afndthseparating and segregating the second ing material which consists in agitating and aerating a pulp of the suitably ground material to produce a coal-bearing froth without addition of an agent and separating and and segregating the froth, then adding an oily agent to the depleted pulp and subjecting the depleted pulp to further agitation and aeration to form a second coalbearing froth, and separating and segregating the second froth.

3. The process of concentrating coal-bearing material which consists in agitating and aerating a pulp of the suitably ground material 'to produce a coalrbearing froth without addition of an agent and separating and segregating the froth, then adding a petroleum oil to the depleted pulp and subjecting the depleted pulp to further a 'tation and aeration to form a. second coalaring froth, and separating and segregating the second froth.

4. The process of separating bright coal from dull coal which consists in agitating and aerating a pulp of finely divided suitable coal to produce a bright-coal-bearing froth without addition of an agent and separating'and segregating the froth, then adding an a ent to the depleted pulp and subjecting t e depleted pulp to further agitation and aeration to form a dull-coalbearing froth, and separating and segregating the second froth.

5. The process of separating bright coal from dull coal which consists in agitating and aerating a pulp of finely divided suitable coal to produce a bright-coal-bearing frothwithout addition of an agent and separating and segregatin the froth, then adding an oily agent to t e depleted-pulp and subjecting the depleted pulp to further agitation and aeration to form a dull-coalbearing froth, and separating and segregating the second froth.

6. The process of separating bright coal from dull coal which consists in agitating and aerating apulp of finely divided suitable coal to produce a bright-coal-bearing froth without addition of an agent and separating and segregating the froth, then add ing a petroleum oil to the depleted pulp and subjecting the depleted pulp to further agitation and .aeration to form a dull-coalbearing froth, and separating and segregating the second froth. Q

In testimony whereof, I have ailixed m signature to this specificatiom' JOHN VIR' QUIGLEY. 

